A pneumatic driving machine—which guides air compressed by an air compressor through use of an air hose and uses the thus-guided air as a power source—is most frequently utilized as a system for driving a common, related-art fastener driving machine, because the driving machine is compact and lightweight. However, the pneumatic driving machine suffers a problem of workability being impaired by the hose which supplies compressed air to the driving machine from the air compressor and which always accompanying the driving machine. Further, a heavy air compressor must be carried in conjunction with the pneumatic driving machine, and hence great inconvenience is encountered in moving and installing the air compressor.
It is disclosed by, for example JP-A-8-205573, that an electric driving machine has been proposed in place of the pneumatic driving machine, wherein a battery (a battery pack) is taken as an energy source and which converts rotational energy of a flywheel rotationally driven by an electric motor into rectilinear kinetic energy used for driving a fastener. This electric driving machine rotates the flywheel by the electric motor, and transmits the rotational energy to a fastener driving mechanism section by a transmission mechanism, such as a clutch, thereby driving a fastener.